But such physiological explanations are not enough to tell us why we dream. Some people believe that dreams are total nonsense, merely the result of the misfiring of electrical impulses in the brain, while on the other hand, some read great importance into even the simplest of dreams. Some dreams reflect inner fears that are instantly recognizable. Dreaming of losing your job or house can reflect real fears, even if they are only subconscious. Most of us have dreamed that we had to take a final exam for a difficult course, which we had never taken, or in which we had done poorly. But what of the dreams that do not have such an obvious meaning? For centuries, both men and women have sought the answers in so-called dream dictionaries, possibly the oldest of which dates back to 5000 BC.